<template>
    <!-- 组件的结构 -->
    <div>
        <h1>当前求和为：{{sum}}</h1>
        <select name="" id="" v-model="n">
            <option :value="1">1</option>
            <option :value="2">2</option>
            <option :value="3">3</option>
        </select>
        <button @click="increment">+</button>
        <button @click="decrement">-</button>
        <button @click="incrementOdd">当前求和为奇数再加</button>
        <button @click="incrementWait">等一等再加</button>
    </div>  
</template>

<script>
    export default{
            name:'Count-test',
            data(){
                return{
                    sum:0,//当前的和
                    n:1//用户选择的数字
                }
            },
            methods:{
                increment(){
                    this.sum+=this.n
                },
                decrement(){
                    this.sum-=this.n
                },
                incrementOdd(){
                    if(this.sum%2==1){
                    this.sum+=this.n
                    }
                },
                incrementWait(){
                    setTimeout(()=>{
                        this.sum+=this.n
                    },500)
                }
            }
            }
</script>

<style scoped>
  button{
        margin-left: 5px;
    }
</style>